Data storage devices use magnetic recording heads to read and/or write data on magnetic storage media, such as a data storage discs. Magnetic recording heads typically include inductive write elements to record data on the storage media. An inductive write element or transducer may include a main pole having a pole tip and one or more return poles. Current is supplied to write coils to induce a flux path in the main pole to record data on one or more magnetic storage layers of the media. Data can be recorded using longitudinal or perpendicular recording techniques. In a perpendicular magnetic recording system, it is desirable to maximize write field strength and also maximize write field gradient to record more data in smaller spaces. In addition, side track erasure (STE) and adjacent track interference (ATI) should be avoided. An increase in write field gradient is typically achieved by providing magnetic shielding adjacent to the write pole. The shield (referred to herein as a front shield or a trailing shield) is separated from the write pole by a non-magnetic gap, referred to herein as a front shield gap (FSG). A conventional magnetic recording head/transducer including a FSG is described below in connection with FIGS. 1A and 1B.
FIGS. 1A and 1B depict air bearing surface (ABS) and side views of a conventional perpendicular magnetic recording (PMR) transducer 10. The conventional PMR transducer 10 may be a part of a merged head including the write transducer 10 and a read transducer (not shown). Alternatively, the magnetic recording head may be a write head only including the write transducer 10.
The write transducer 10 includes an under-layer/substrate 12, a main pole 16, a front shield 18 and side shields 20. The under-layer 12 may include multiple structures which are under the pole 16. The write transducer 10 may also include other components including but not limited to coils (denoted by reference numeral 11 in FIG. 1B) for energizing the main pole 16.
The main pole 16 resides over under-layer 12 and includes sidewalls 22 and 24. Sidewalls 22 and 24 are separated from the side shields 20 by non-magnetic side shield gaps (SSGs) 26. The top (trailing) surface of the main pole 16 also has a beveled portion 17. A FSG 28 is formed between the front shield 18 and the main pole 16. In a conventional write head/transducer such as 10, the FSG 28 extends over or outside the SSGs 26 in a cross-track direction, forming overhangs 30 that separate the front shield 18 from portions of the side shields 20. The overhangs 30 may be produced by a write head fabrication process that employs photo patterning to define a shape and dimensions of FSG 28 as part of the steps for its formation. A recording head with such a FSG design may have certain on-track performance advantages, but may also produce STE and ATI which may be detrimental to a reliability of the recording head, particularly at high data-writing rates.